The present invention relates to a transmission controller that electrically switches the position of a vehicle transmission.
Japanese Unexamined Patent Publication Ser. No. 5-272633 discloses a vehicle transmission controller. In this transmission controller, a shift controller controls a gear change actuator based on a manipulation of the shift lever of a shifting device including a park position (P), a neutral position (N), a drive position (D), and a reverse position (R).
To move a vehicle equipped with such a transmission controller from a standstill, a driver starts the engine while maintaining the transmission in the park position or the neutral position and then manually moves the shift lever to switch the gear train of the automatic transmission to the drive position. This allows the driver to drive the vehicle. In this drive condition, the transmission controller automatically switches the transmission in accordance with the vehicle speed and the throttle angle, or throttle position.
To park the vehicle, the driver shifts the shift lever to switch the transmission to the park position from the drive position or from the reverse position. This locks the output shaft of the transmission to prevent the vehicle from moving by itself accidentally.
However, when the driver wants to drive the vehicle forward from a parked state, the driver might operate the shift lever erroneously, with the result that the transmission is shifted to the reverse position from the park position, which causes the vehicle to move backward. Also, a driver might drive the vehicle forward by mistake when the driver intends to drive backward from the parked state.
To temporarily stop the engine, or to idle the engine, the shift lever is switched to the neutral position or to the park position from the drive position when the vehicle is stopped. Then, the ignition switch is turned off. To drive the vehicle again, the engine is re-started by turning the ignition switch while depressing the brake pedal. Then, the shift lever is switched to the drive position from the neutral position or from the park position, and the accelerator is pressed. That is, idling the engine requires shifting the shift lever.
Also, there is a case where the driver may leave the vehicle with the engine running, the parking brake applied, and the shift lever in the drive position. However, in such a condition, the vehicle might accidentally move by itself if the idle speed is increased by an automatic control procedure.
Additionally, if a collision occurs and an air bag is actuated, the driver would not be able to continue driving the vehicle, and the vehicle would stop with the transmission in the drive position. This might cause the vehicle to move by itself accidentally.
Accordingly, it is an object of the present invention to provide a vehicle transmission controller that automatically switches a transmission to a proper engagement position in accordance with the state of the vehicle.
To achieve the above object, the present invention provides a vehicle transmission controller that controls switching of the gear position of a transmission. The controller includes a manipulator that is manipulated to select a gear position of the transmission. The controller further includes an actuator that actuates the transmission to switch the gear position in accordance with a manipulation of the manipulator. The actuator switches the transmission to the gear position selected by the manipulator. Also, the actuator switches the transmission to a predetermined gear position from the gear position selected by the manipulator when the vehicle satisfies predetermined conditions.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.